In order to protect the head, a helmet is required to withstand certain impact strength, and cannot be too heavy to affect the use at the same time, therefore the existing helmet generally includes an outer shell made of PC and an inner shell made of EPS and other lightweight materials. The outer shell is made of the PC by blister forming, and the EPS and other lightweight materials are subjected to pressure injection to form a helmet main body with the outer shell.
Usually, for the beautiful appearance of the helmet, the colorless PC material needs to be colored, the shape of the PC material is irregular after the blister forming, and the coloring difficulty on the outer shell is high, therefore the PC material needs to be colored by silk screen printing, coating and other manner prior to the blister forming. With respect to the existing luminous helmet with pre-embedded LED light bars, blanks need to be reserved on positions of the pre-embedded LED light bars, namely blanks are reserved and are not colored for the transmission of light. As the blanks need to be reserved prior to the blister forming of the PC material, deformation is generated during the blister forming of the PC material, therefore the blank areas may be subjected to deviation, resulting in deviation between the positions of the reserved blanks and the positions of the pre-embedded LED light bars, which not only affects the light emission effect, but also affects the beautiful appearance, and accordingly the percent defective in helmet production is increased.